Dual mode devices (DMDs), such as dual mode handsets, PDAs, laptops, and other mobile wireless devices, have a cellular radio transceiver for access to a carrier's radio access network (RAN) and a wireless fidelity (WiFi) radio transceiver for access to a wireless local area network (LAN). These dual mode devices can advantageously utilize WiFi networks when available and fill in gaps between WiFi networks using a carrier-managed network, such as the cellular network.
There are many reasons why the WiFi network may be preferable to the user and the carrier. The WiFi network may be free to the carrier and would reduce the cost associated with setting up a call for a dual mode device because the access point (AP) operator and service provider (SP) providing bandwidth may be different parties. The carrier may also provide improved convenience to the subscriber by only requiring the use of one phone while also extending wireless coverage to the subscriber's home, where the carrier-managed system may not reach or may not reach well. Furthermore, the carrier may lower transmission costs by using the Internet to move voice traffic to the carrier's network, thereby using less time on the carrier's network and increasing revenue. The dual mode device may also gain access to additional features when in a WiFi LAN.
A problem with Voice over Internet Protocol (VoIP) services is that the service provider does not have reliable geographic location data on the CPE, such as access points. Even when a subscriber has registered with the system, the service provider cannot be certain that the subscriber has not physically moved the CPE without notifying the service provider. Network and AP information may change on a regular basis as new hotspots are created, existing hotspots are turned off, and roaming agreements are created/concluded. A dangerous impact of incorrect or inaccurate geolocation information is that emergency services may be sent to incorrect locations.
Embodiments of the present invention and their advantages are best understood by referring to the detailed description that follows. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures.